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Neutron spectroscopy

Neutron spectroscopy probes the dynamics of magnetic moments, molecules and lattices over length scales ranging from a few angstroms to tens of nanometers, and over timescales from tens of femtoseconds up to the microsecond. Within neutron spectroscopy, there are 4 main techniques which use different methods to determine the energy of the incident and scattered neutrons and are adapted to different kinds of scientific studies.

Time-of-flight spectrometry

There are 3 dedicated time-of-flight (TOF) spectrometers (IN5, SHARP+ and PANTHER) which use the time-of-flight of neutrons through the spectrometer to determine the energies of the incident and scattered neutrons. The instruments are optimized for different kinds of scientific studies, which depends mainly on their energy resolution and momentum transfer range.

An overview of instrument parameters is provided in the table below to help you choose the most suitable instrument. By clicking on the instrument, you can go directly to the dedicated instrument pages where more information can be found, including scientific highlights and contact details for the instrument scientists.

 IN5SHARP+PANTHER
λ (Å)1.5151.51.51.51.51.51.51.51.51.5
energy resolution (meV)1.51.51.51.51.51.51.51.51.51.51.5
energy transfer (meV)1.51.51.51.51.51.51.51.51.51.51.5
Qmin (A-1)0.40.00.30.20.20.20.50.30.20.70.4
Qmax (A-1)1.51.51.51.51.51.51.51.51.51.51.5
Detector definition angle
minimum - maximum
5-13510-1155-136
Comments      PG(004)

PG(004)

/(002)

PG(002)Cu(220)Cu(220)
      Energy resolution assumed to be 5.5% DeltaEi/Ei
PG(004)(002) designates maximum wavelength for PG(004) and minimum wavelength for PG(002

Vibratrional spectrometrer

 IN1-LAGRANGE
λ (Å)0.44.26
energy resolution (meV)2-3% of Ei 
incident energy (meV)  
energy transfer (meV)0-500 
Qmin (A-1)0,86 (reached at Ei=4,5meV) 
Qmax (A-1)15 (at Ei=500meV) 
Detector definition angle
minimum - maximum
  
Comments Scanning instrument, so the incident wavelength can be changed from 0,4 up to 4,26

Triple-axis spectrometry

There is a range of triple-axis (TAS) spectrometers which use crystal monochromators and analysers to determine the incident and scattered neutron energies. TAS spectrometers are mainly used to study single crystal samples, focusing on specific regions of interest in reciprocal space. The TAS instruments are optmised for different kinds of scientific studies, which depends for example on the energy and flux of the incident neutron beam, polarized neutron capability and the availability of specific sample environments.

An overview of instrument parameters is provided in the table below to help you choose the most suitable instrument. By clicking on the instrument, you can go directly to the dedicated instrument pages where more information can be found, including scientific highlights and contact details for the instrument scientists.

InstrumentThALESIN8
MonochromatorPG002Si111HeuslerPG002Cu200Si111Si311
Incident wave-number (Å-1)

2.8,
<1.5,
1.2

2.8,
1.5,
1.2
2, 1.54.154.1 
Incident flux (n/cm2/s)2.4*108,
1.2*108,
5*107
1.3*108,
4*107,
3*107
2.7*107,
2*107
1095*1085*1082.5*108
Energy resolution (meV)

0.8,
<0.12,
0.06

0.8,
0.12,
0.06

0.4,
0.2

1.1 
PG002 analyser, kf=2.662 Å-1

0.9
PG002 analyser, kf = 2.662 Å-1
0.55
(Cu200 analyser, kf = 2.662 Å-1)

1.0
PG002 analyser, kf = 2.662 Å-1)

2.2 
(PG002 analyser, kf = 4.1 Å-1)

Angular range (°)120120120120120120120
Comments- FlatCone
- Velocity selector

-High magnetic fields
FlatCone
- High  magnetic fields

 

Polarised neutrons  FlatConeFlatCone
InstrumentIN12IN20IN22
MonochromatorPG002PG002 + PolariserHeusler (Cu2MnAl)111Si111PG002Heusler111Cu111
Incident wave-number (Å-1)2.8,
2, 1
2.8,
2, 1
4.54.51.55,
2.662,
4.15,
6.0
1.55,
2.662,
4.15,
6.0
2.662,
4.15,
6.0,
7.4
Incident flux (n/cm2/s)8.107,
108,
2.107
2.8.107,
3.5.107,
6.106
1082*1086.0x106,
27x106,
58x106,
25x106
1.3x106,
6.0x106,
13x106,
5.0x106
9.0x106, 19x106,
16x106, 2.8x106
Energy resolution (meV)1,
0.4,
0.04

1,
0.4,
0.04

3 to 10% (incident energy)3 to 10% (incident energy)

0.25,
1,
4,
12

0.25,
1,
4,
12

 
Angular range (°)120120120120120120120
Comments

Velocity selector

High magnetic fields


Velocity selector
Polarised neutrons
CRYOPAD
High magnetic field for 1/2pol
Polarised neutrons
Cryopad
FlatCone
PASTIS
FlatCone
High Magnetic Fields
High magnetic fields
40T option

Neutrons Spin echo option (ZETA)
Polarised neutrons
CRYOPAD
High magnetic fields

High magnetic fields

Neutron backscattering

Neutron backscattering provides higher energy resolution than TOF or TAS by using crystal analysers that operate in a backscattering geometry. There are 2 dedicated spectrometers which differ essentially in terms of the energy of the incident neutrons and thus the energy resolution and momentum transfer. IN16b is a very versatile instrument which includes a time-of-flight option to significantly increase the dynamic range.

An overview of instrument parameters is provided in the table below to help you choose the most suitable instrument. By clicking on the instrument, you can go directly to the dedicated instrument pages where more information can be found, including scientific highlights and contact details for the instrument scientists.

 IN13IN16B
λ (Å) 2.236.276.27 (BATS)3.27
Energy resolution (μeV)80.75 or 0.31.5 to 82
Energy transfer-100 to 100-30 to +30-700 to +300-59 to +59
Qmin0.30.10.10.7
Qmax4.91.81.83.5
Commentshigher Qstandard
configuration
TOF extended
dynamic range
high Q

 


Neutron spin-echo

Spin Echo Spectroscopy (NSE) achieves very high energy resolution using the change in polarization between the incident and scattered neutron beams to measure small energy changes due to the dynamics in the sample. The energy resolution is better than that of neutron backscattering and is expressed in Fourier times since the technique measures directly the intermediate scattering function I(Q,t). There are 2 dedicated spectrometers which differ essentially in terms of the detector coverage and therefore the count rate. IN15 holds the record for measuring the longest Fourier time – about 1 microsecond.

An overview of instrument parameters is provided in the table below to help you choose the most suitable instrument. By clicking on the instrument, you can go directly to the dedicated instrument pages where more information can be found, including scientific highlights and contact details for the instrument scientists.

 IN11IN15WASP
λ (Å)3.8126173.810
Fourier time (s) min  4*10-1290*10-123*10-125*10-12
Fourier time (s) max  42*10-91*10-63.4*10-962*10-9
Qmin 0.030.020.430.16
Qmax 1.20.4231.14
Commentsremoved from schedule  expected performance